The use of steam to grow oxides on semiconductor wafers is well known and has been used extensively in the past. Typical temperatures of the steam are about 900.degree. to 1,000.degree. C. and pressures are about 10 to 25 atmospheres. At these operating conditions, a single wafer in a batch of wafers can be processed but at a relatively slow rate, such as 2 hours or more. It is often desirable to have a high throughput while providing for acceptable process conditions.
Due to industry trends, processing of wafers is being done in smaller batches and ultimately, processing will be done with single wafers. The reasons for this single wafer trend include greater control of the wafer, the high cost of the wafers, and the size of the wafers. It is much easier to control a single wafer during processing than it is to control a batch of wafers. Moreover, the cost of a wafer is relatively high and with greater wafer control, the possibility of wafer damage or breakage is minimized. Furthermore, the size of wafers is increasing. Typically, 6" wafers are now being used and it foreseeable that 8" and 10" wafers will be used in the future. Because of the foregoing problems, a need exists for improvements in the processing of semiconductor wafers as described above so that the processing can be economically feasible as a single wafer process system. The present invention satisfies this need.
Disclosures relating to the field of the present invention include U.S. Pat. Nos. 4,167,915, 4,268,538, 4,315,479 and 4,599,247.